Optical Element Overhang Design for Stress Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical elements produced by conventional methods are prone to separation and deformation due to stress and thermal changes, which affect the optical function parts.
Innovation Solution
The optical element features a concave curved surface on the formed layer that matches the inner surface of the base, with an overhang on the base's surface to absorb stress and shrinkage, preventing separation and deformation. The overhang is embedded in a groove to enhance fixing strength and control spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the formed layer is provided in the depression of the base by pressing a forming mold, then the optical element can be produced with integrated structure, but stress concentrates on the depression causing separation of the formed layer from the base
Solution Approach 1:
The formed layer is divided into two distinct portions: a first portion positioned in the depression and a second portion extending onto the front surface of the base. This segmentation allows stress to be distributed across different regions, preventing concentration at the depression interface and thereby preventing separation between the formed layer and base.
Solution Approach 2:
The formed layer transitions from a two-dimensional configuration (flat layer) to a three-dimensional configuration by extending the second portion onto the front surface of the base. This dimensional change creates an overhang structure that provides additional bonding area and stress distribution pathways, enhancing reliability without complicating the manufacturing process.
2Productivity
If the formed layer is cured in the depression, then the optical element can be manufactured efficiently, but shrinkage during curing deforms the optical function part
Solution Approach 1:
Dividing the formed layer into first and second portions allows the optical function part (in the first portion) to be isolated from the shrinkage-prone region (second portion). The gradual thickness change in the first portion ensures that curing shrinkage occurs primarily in the second portion, preventing deformation of the precise optical surfaces.
Solution Approach 2:
The first portion is designed with a predetermined thickness that provides local quality optimization: it maintains sufficient structural integrity and optical precision while being thin enough to minimize shrinkage impact. The second portion has greater thickness to absorb shrinkage, creating localized quality zones that resolve the contradiction between efficiency and precision.
3Device complexity
If the formed layer thickness varies abruptly, then the manufacturing process is simplified, but shrinkage effects are amplified causing deformation
Solution Approach 1:
The first portion features a curved surface with gradual thickness transition instead of abrupt changes. This curvature design simplifies the manufacturing process by using smooth forming molds while simultaneously reducing stress concentration and shrinkage effects that would cause deformation, thus resolving the contradiction between process simplicity and precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents separation and deformation of the formed layer and optical function parts, ensuring stable performance under thermal changes and curing processes.
Implementation Method 1
curing the resin material
Implementation Method 2
shrinkage caused in the first portion, for example, when the formed layer is cured
Implementation Method 3
optical function part such as a grating
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An optical element includes a base having a curved depression formed in a front surface thereof and a formed layer arranged on the base. The formed layer includes a main part in the depression as viewed from a depth direction of the depression and an overhang on the front surface of the base while connecting to the main part. An opposite surface of the main part to a surface thereof on a side of an inner surface of the depression is formed like a concave curve that is concave in a same direction as the inner surface of the depression. A predetermined surface of the main part that is opposed to the inner surface of the depression is provided with an optical function part.